The capture of a high-quality image associated with a moving subject in a low-lighting situation is necessary for object monitoring and inspection applications such as, for example, a biometric acquisition system. Image capturing devices such as, for example, a digital camera often utilize flashes to provide a complementary light source during an image capturing process.
In some conventional image capturing devices, the capture of the high-quality image can be accomplished by the use of one or more short-duration flashes fired simultaneously. Such an approach consumes more electric power. Thus, proper exposure compensation cannot be achieved due to the inability to adjust flash intensity immediately. Additionally, the power of a point flash falls off rapidly with distance and the amount of power required to illuminate the distant subject can rapidly exceed the illumination power of a battery of flashes. Furthermore, the amount of power that a flash may need to sufficiently illuminate the distant subject may easily exceed eye safety limits. Some prior art approaches have attempted to solve such problems by spreading the flash output over a longer time (i.e. staggering multiple flashes in time). However, non-stationary objects in a scene may appear ghosted in a resulting image. Also, processing such image to recover a sharp image may amplify noise and introduce other artifacts.
Based on the foregoing, it is believed that a need exists for an improved system and method for encoding appearance of a moving subject utilizing a fluttering flash. A need also exists for an improved method for acquiring a sufficiently exposed and sharp image associated with the moving subject in a low-light situation, as described in greater detail herein.